We develop a systematically parameterized non-orthogonal, multi-orbital tight-binding (TB) framework to accurately model the electronic structure of small-diameter armchair carbon nanotubes, with a particular focus on their suitability for quantum-level manipulation. Our approach explicitly treats the overlap matrix and curvature-induced σ–π hybridization within a generalized eigenvalue formulation, allowing essential curvature effects to be captured at the single-particle level without relying on empirical band corrections. The key advancement of this work lies in a benchmark-driven calibration strategy. The distance-decay parameters (β, βoverlap) governing the Slater–Koster integrals are calibrated against a well-established low-energy benchmark and subsequently validated across multiple independent electronic properties. This procedure yields a single, transferable parameter set that consistently captures the essential low-energy electronic characteristics arising from curvature effects in small-diameter armchair carbon nanotubes. The resulting electronic structure description is internally consistent and robust across different tube diameters, providing a reliable foundation for further quantum-level analysis. Based on this validated single-particle framework, we investigate finite-length armchair carbon nanotubes as candidate platforms for electrically driven quantum control. By analyzing the low-energy spectrum and its response to time-dependent electric fields, we explore coherent qubit manipulation protocols enabled by curvature-modified electronic states. We evaluate electrically driven Rabi oscillations under experimentally realistic driving amplitudes and coupling strengths. Our results indicate that fast π-pulse operations with durations on the order of 0.23–0.28 ns are achievable within the parameter regime considered in this work, highlighting the potential of these systems for rapid quantum gate operations.